PUBIC LICE
VECTOR BIOLOGY
Three types of lice:
• Head lice: Pediculus humanus
capitis (2-3 mm long)
• Body lice: Pediculus humanus
humanus (2.3-3.6 mm long)
• Pubic lice (crabs): Phthirus
pubis (1.1-1.8 mm long)
CRABS
• Phthirus pubis
• The pubic or crab louse
• An ectoparasite whose only host are humans
• Ectoparasite is a parasite that lives outside of its host
VECTOR BIOLOGY
All three types of lice:
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•
•
•
Are ectoparasites: lice live on the surface of the host
Move by crawling, as opposed to flying
Have humans as their only host
Have similar life cycles
Head Lice
Body Lice
Pubic Lice
EPIDEMIOLOGY & RISK FACTORS
Pubic Lice (“Crabs”):
• Current worldwide prevalence estimated 2%
• Spread through sexual contact and is
considered an STD
• Can be spread through fomites: contact with
clothing, linens, and towels belonging to an
infected person.
• Pubic lice found on children can be an indicator
of sexual abuse.
SIGNS & SYMPTOMS
• Itiching or pruritus in the groin area is the most
common symptom
• Secondary bacterial infection can occur from scratching
the skin
• Visible lice eggs (nits) or lice crawling or attached to
pubic hair or other body hair are signs of pubic lice
infestation
• Pubic lice on the head (eyelashes or eyebrows) of a
child may be an indication of sexual exposure or
abuse
LICE LIFE CYCLE
Lice stages:
1. Egg/nit
2. Nymph (3 molts)
3. Adult
Both nymphs and adults take
blood meals from the human
host.
LIFE CYCLE
• Pubic Lice have three stages:
• Egg
• Nymph
• Adult
• Females will lay approximately 30 eggs during their 3–4
week life span.
• Eggs hatch after about a week and become nymphs
• They look like smaller versions of the adults. The nymphs
undergo three molts
• Adults are much broader in comparison to head and
body lice. Adults are found only on the human host and
require human blood to survive.
DISEASE
• Head lice: does not
spread disease
• Body lice spreads
bacterial disease!
• Pubic lice: does not
spread disease
EPIDEMIOLOGY & RISK FACTORS
(CONTINUED)
Pubic Lice (“Crabs”):
• Current worldwide prevalence estimated 2%
• Spread through sexual contact and is considered an STD
• Can be spread through fomites: contact with clothing,
linens, and towels belonging to an infected person.
• Pubic lice found on children can be an indicator of sexual
abuse.
PREVENTION AND CONTROL
• Sexual contact should be avoided with people who
are infested
• Machine wash and dry clothing worn and bedding
used by infested person in hot water (at least 130°F)
and high heat drying
• Do not share clothing, bedding and towels with an
infested person
• Fumigation is not necessary to control pubic lice
VULVOVAGINITIS
VAGINITIS
• Bacterial Vaginosis (BV)
• Vulvovaginal Candidiasis (VVC)
• Trichomoniasis
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VAGINAL ENVIRONMENT
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•
•
•
•
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The vagina is a dynamic ecosystem that contains
approximately 109 bacterial colony-forming units.
Normal vaginal discharge is clear to white, odorless,
and of high viscosity.
Normal bacterial flora is dominated by lactobacilli –
other potential pathogens present.
Lactic acid helps to maintain a normal vaginal pH
of 3.8 to 4.2.
Acidic environment and other host immune factors
inhibits the overgrowth of bacteria.
Some lactobacilli also produce H2O2, a potent
microbicide.
VAGINITIS
• Usually characterized
by
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•
•
•
Vaginal discharge
Vulvar itching
Irritation
Odor
• Common types
• Bacterial vaginosis
(40%–45%)
• Vulvovaginal
candidiasis (20%–25%)
• Trichomoniasis (15%–
20%)
OTHER CAUSES OF VAGINITIS
• Normal physiologic
variation
• Allergic reactions
• Herpes simplex virus
• Atrophic vaginitis
• Foreign bodies
PREPARATION AND EVALUATION
OF SPECIMEN
• Collection of specimen
• Preparation of specimen slide
• Examination of specimen slide
• wet mount
• Whiff test
• Vaginal pH
WET PREP: COMMON
CHARACTERISTICS
RBCs
Saline: 40X objective
PMN
Sperm
RBCs
Squamous
epithelial cell
Artifact
Source: Seattle
18
STD/HIV Prevention Training Center at the University of Washington
WET PREP: LACTOBACILLI AND
EPITHELIAL CELLS
Lactobacilli
Saline: 40X objective
Lactobacilli
Artifact
NOT a clue cell
Source: Seattle
STD/HIV Prevention Training Center at the University of Washington
VAGINITIS DIFFERENTIATION
Normal
Bacterial Vaginosis
Candidiasis
Trichomoniasis
Symptom
presentation
Odor, discharge, itch
Itch, discomfort,
dysuria, thick
discharge
Itch, discharge, ~70%
asymptomatic
Vaginal discharge
Homogenous,
adherent, thin, milky
white; malodorous
“foul fishy”
Thick, clumpy, white
“cottage cheese”
Frothy, gray or yellowgreen; malodorous
Inflammation and
erythema
Cervical petechiae
“strawberry cervix”
Clear to
white
Clinical findings
Vaginal pH
3.8 - 4.2
> 4.5
Usually < 4.5
> 4.5
KOH “whiff” test
Negative
Positive
Negative
Often positive
Lacto-bacilli
Clue cells (> 20%),
no/few WBCs
Few to many
WBCs
Motile flagellated
protozoa, many
WBCs
NaCl wet mount
KOH wet mount
Pseudohyphae or
spores if non-albicans
species
BACTERIAL VAGINOSIS (BV)
BACTERIAL VAGINOSIS (BV)
EPIDEMIOLOGY
• Most common cause of vaginitis
• Prevalence varies by population
• 5%–25% among college students
• 12%–61% among STD patients
• Widely distributed
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EPIDEMIOLOGY
• BV linked to
• Premature rupture of membranes
• Premature delivery and low birth-weight
delivery
• Acquisition of HIV, N. gonorrhoeae, C.
trachomatis, and HSV- 2
• Development of PID
• Post-operative infections after gynecological
procedures
RISK FACTORS
• African American
• Two or more sex partners in previous six
months/new sex partner
• Douching
• Lack of barrier protection
• Absence of or decrease in lactobacilli
• Lack of H2O2-producing lactobacilli
TRANSMISSION
• Currently not considered a sexually transmitted
disease, but acquisition appears to be related to
sexual activity.
MICROBIOLOGY
• Overgrowth of bacteria species normally
present in vagina with anaerobic bacteria
• BV correlates with a decrease or loss of
protective lactobacilli
• Vaginal acid pH normally maintained by lactobacilli
through metabolism of glycogen.
• Hydrogen peroxide (H2O2) is produced by some
Lactobacilli,sp.
• H2O2 helps maintain a low pH, which inhibits bacteria
overgrowth.
• Loss of protective lactobacilli may lead to BV.
CLINICAL PRESENTATION AND
SYMPTOMS
• Many women (50%–60%)
are asymptomatic.
• Signs/symptoms, when
present
• Reported malodorous (fishy
smelling) vaginal discharge
• Reported more commonly
after vaginal intercourse and
after completion of menses
• Symptoms may remit
spontaneously.
TREATMENT
CDC-recommended regimens
• Metronidazole 500 mg orally twice a
day for 7 days
or
• Metronidazole gel 0.75%, one full
applicator (5 g) intravaginally, once or
twice a day for 5 days
or
• Clindamycin cream 2%, one full
applicator (5 g) intravaginally at
bedtime for 7 days
PARTNER MANAGEMENT
• Relapse or recurrence is not affected by treatment of
sex partner(s).
• Routine treatment of sex partners is not recommended.
VAGINITIS
VULVOVAGINAL CANDIDIASIS (VVC)
VVC EPIDEMIOLOGY
• Affects most females during lifetime, with
approximately 50% having two or more episodes
• Most cases caused by C. albicans (85%–90%)
• Second most common cause of vaginitis
• Estimated cost: $1 billion annually in the U.S.
TRANSMISSION
• Candida species are normal flora of skin and
vagina and are not considered to be sexually
transmitted pathogens.
MICROBIOLOGY
• Candida species are normal flora of the
skin and vagina.
• VVC is caused by overgrowth of C.
albicans and other non-albicans species.
• Yeast grows as oval budding yeast cells
or as a chain of cells (pseudohyphae).
• Symptomatic clinical infection occurs
with excessive growth of yeast.
• Disruption of normal vaginal ecology or
host immunity can predispose to vaginal
yeast infections.
CLINICAL PRESENTATION AND
SYMPTOMS
•
Vulvar pruritis is most common symptom.
•
Thick, white, curdy vaginal discharge ("cottage
cheese-like")
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Erythema, irritation, occasional erythematous
"satellite" lesion
•
External dysuria and dyspareunia
34
057
VULVOVAGINAL CANDIDIASIS
Source: Health Canada, Sexual Health and STI Section, Clinical Slide Gallery
063
064
065
THRUSH
DIAGNOSIS
• History, signs and symptoms
• Visualization of pseudohyphae (mycelia) and/or
budding yeast (conidia) on KOH or saline wet
prep
• pH normal (4.0 to 4.5)
• If pH > 4.5, consider concurrent BV or trichomoniasis
infection
• Cultures not useful for routine diagnosis
UNCOMPLICATED VVC
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Mild to moderate signs and symptoms
Nonrecurrent
75% of women have at least one episode
Responds to short course regimen
43
CDC-RECOMMENDED TREATMENT REGIMENS
FOR UNCOMPLICATED VVC
Over-the-Counter Intravaginal Agents
• Butoconazole 2% cream, 5 g intravaginally for 3 days or
• Clotrimazole 1% cream 5 g intravaginally for 7-14 days or
• Fluconazole 150 mg oral tablet, 1 tablet in a single dose
Note: The creams and suppositories in these regimens are oil-based and may weaken latex condoms and
diaphragms. Refer to condom product labeling for further information.
COMPLICATED VVC
• Recurrent (RVVC)
• Four or more episodes in one year
• Severe
• Edema
• Excoriation/fissure formation
• Non-albicans candidiasis
• Compromised host
COMPLICATED VVC TREATMENT
• Recurrent VVC (RVVC)
• 7–14 days of topical therapy, or
• 100 mg, 150 mg , or 200 mg oral dose of fluconozole
repeated every 3 days (days 1,4,and 7)
• Maintenance regimens (see 2010 CDC STD treatment
guidelines)
• Severe VVC
• 7–14 days of topical therapy, or
• 150 mg oral dose of fluconozole repeated in 72 hours
46
PARTNER MANAGEMENT
• VVC is not usually acquired through sexual
intercourse.
• Treatment of sex partners is not
recommended.
• A minority of male sex partners may have
balanitis and may benefit from treatment
with topical antifungal agents to relieve
symptoms.
PATIENT COUNSELING AND EDUCATION
• Nature of the disease
• Normal vs. abnormal vaginal discharge, signs and
symptoms of candidiasis, maintain normal vaginal flora
• Transmission Issues
• Not sexually transmitted
• Risk reduction
• Avoid douching, avoid unnecessary antibiotic use,
complete course of treatment
TRICHOMINIASIS
BACKGROUND
• Trichomoniasis is a sexually transmitted infection (STI)
caused by the motile parasitic protozoan
Trichomonas vaginalis.
• It is one of the most common STIs, both in the United
States and worldwide.
• Infection with T Vaginalis increases the risk of HIV
transmission in both men and women
• Trichominiasis is also associated with adverse
pregnancy outcomes, infertility, and cervical
neoplasmia
• Humans are the only host of T Vaginalis
• Infection is predominantly by sexual intercourse
EPIDEMIOLOGY
• Trichomoniasis is one of the most common STIs in the
United States, with a prevalence estimated at 8
million cases annually
• Multiple studies have found that T vaginalis
infection is less prevalent in men than in women.
• In female adolescents, trichomoniasis is more
common than gonorrhea
• This is particularly disconcerting in that it increases
susceptibility to other infections
• Unlike other STIs, trichomoniasis generally becomes
more common with age and lifetime number of
sexual partners
ETIOLOGY
• Risk factors for T vaginalis infection include:
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New or multiple partners
A history of STIs
Current STIs
Sexual contact with an infected partner
Exchanging sex for money or drugs
Using injection drugs
Not using barrier contraception (eg, because of oral
contraceptives)
RISK FACTORS
• Multiple sexual partners
• Lower socioeconomic status
• History of STDs
• Lack of condom use
SIGNS AND SYMPTOMS
• When trichomoniasis does cause symptoms, they
can range from mild irritation to severe
inflammation.
• Some people with symptoms get them within 5 to 28
days after being infected, but others do not
develop symptoms until much later.
• Women
• Women with trichomoniasis may notice itching, burning,
redness or soreness of the genitals, discomfort with urination,
or a thin discharge with an unusual smell that can be clear,
white, yellowish, or greenish.
CLINICAL PRESENTATION IN WOMEN
• Common sites of T vaginalis infection include the
vagina, urethra and endocervix
• Symptoms include vaginal discharge, itching, odor,
dysuria (though commonly asymptomatic)
• Elevated vaginal pH
• Forthy discharge and strawberry cervix are classical
findings on exam
“STRAWBERRY CERVIX” DUE TO T.
VAGINALIS
Source: Claire
E. Stevens/Seattle STD/HIV Prevention
Training Center at the University of Washington
56
CLINICAL PRESENTATION IN MEN
• Non-gonococcal, non-chlamydial urethritis
• Symptoms include urethral discharge, dysuria
(though commonly asymptomatic)
• T. vaginalis can be isolated form men with chronic
prostatitis
PATHOPHYSIOLOGY
• T Vaginalis is approximately the size of a white
blood cell (WBC)
• It has 4 flagella anteriorly and 1 flagellum posteriorly
LIFE CYCLE OF TRICHOMONAS
VAGINALIS.
• T vaginalis trophozoite resides in female lower
genital tract and in male urethra and prostate
• It replicates by binary fission
• The parasite does not survive well in the external
environment.
• T vaginalis is transmitted among humans, the only
known host, primarily via sexual intercourse
PATHOPHYSIOLOGY
• In women, T vaginalis is isolated from the vagina,
cervix, urethra, bladder, and Bartholin and Skene
glands.
• During infection, the vaginal pH increases, as does the
number of polymorphonuclear leukocytes (PMNs).
• Symptoms of trichomoniasis typically occur after an
incubation period of 4-28 days.
• Infection may persist for long periods in women
• Some infections may persist for months or even years
PATHOPHYSIOLOGY
• In men, the organism is found in the anterior urethra,
external genitalia, prostate, epididymis, and semen.
• It resides the urogenital tract as well
• Infections only persist for up to 10 days in males
RACE DEMOGRAPHICS
• In the National Longitudinal Study of Adolescent
Health Study, significant differences in the
prevalence of trichomoniasis among adolescents
were noted by race:
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White, 1.2%;
Asian, 1.8%;
Latino, 2.1%;
Native American, 4.1%;
African American, 6.9%
TREATMENT
• Oral Metronidazole (Flagyl)
• Treatment of choice
• Cure rates of 86-100%
PROGNOSIS
• Pregnant women with T vaginalis infection are more
likely than uninfected women to deliver preterm or
to have other adverse pregnancy outcomes
• Including low birth weight, premature rupture of
membranes, and intrauterine infection.
• Respiratory or genital infection in the newborn may
also occur
• T vaginalis infection may also increase the vertical
transmission of HIV due to a disruption of the vaginal
mucosa.
• Trichomoniasis may also play a role in cervical
neoplasia and postoperative infections
PARTNER MANAGEMENT
• Sex partners should be treated.
• Patients should be instructed to avoid sex until they
and their sex partners are cured (when therapy has
been completed and patient and partner(s) are
asymptomatic, about 7 days).
PATIENT COUNSELING AND
EDUCATION
• Nature of the disease
• May be asymptomatic in both men and women,
in women may persist for months to years,
untreated trichomoniasis might be associated
with adverse pregnancy outcomes, douching
may worsen vaginal discharge, alcohol
consumption is contraindicated with
metronidazole
• Transmission issues
• Almost always sexually transmitted, fomite
transmission rare, might be associated with
increased susceptibility to HIV acquisition